FLOATING ISLANDS exist in some lakes, and more rarely in slow and placid rivers. Not tin frequently they are formed by the detachment of portions of the bank; the interlaced roots of plants forming a fabric sufficiently strung to endure the occasional buffeting of waves, and to support soil for herbage or even trees to grow in. F. 1. are often formed by aggregation of Vrift-wood in the creeks and bays of tropical rivers, and being wafted into the channel of the river when it is flooded or by the wind, are carried down to the sea, with the soil that has accumulated, and.the vegetation that has established itself upon them. They are sometimes seen at a distance of 50 or 100 m. from the mouth of the Ganges, with living trees standing erect upon them. Portions of the alluvial soil from the deltas of rivers, held together by the roots of mangroves and other trees, are sometimes also carried out to sea after typhoons or hurricanes, and ships have, in consequence, been involved in unexpected dangers, as amongst the icebergs of, colder latitudes. Imagination has always invested with a peculiar interest the Straggling plots, which to and five doe rome In the wide waters: and ancient legend did not fail to notice the floating islets of the sacred Vadimonian lake, which wereffe to bear away cattle that were tempted upon them by their fresh green grass; and the island of the Cutiliama waters, which carried on its surface a dark and gloomy grove, and was constantly changing its place. A small lake in Artois, near St. Omer, is remarkable for the number of its F. I., as arc also the marshy lakes of Comacchio, near the gulf of Venice. Amonf, the largest in the world are those of the lake of Gerdau, in Prussia, which furnish pastur_ge for 100 head of cattle; and that of the lake of Kolk, in Osnabruck, which is covered with •beautiful elms. Loch Lomond was long celebrated for its floating island; it, however, can no longer boast of one, as it has long since subsided and become stationary. F. I., arc found in some lakes of Scotland, and also in, Ireland, and consist for the most part of large float ing masses of peat. Pennant gives a description of one which lie saw in Breadalbane, the surface of which exhibited plenty of coarse grass, small willows, and even a little birch tree. More interesting to the scientific inquirer, as presenting a phenomenon not so easily explained, are those F. I. which from time to time appear and disap pear in the same spot, of which there is one in the lake of Derwentwater in Cumber land, one in the lake Malang in the province of Smalande in Sweden, and one in Ostro gothic. That in Derweutwater is opposite to the mouth of a stream called the Cargill; and the most probable of the many theories which have been proposed to account for it is that which ascribes it to the waters of the stream, when flooded by rains, getting beneath the interlaced and matted roots of .the aquatic plants which there form a close turf on
the bottom of the lake. This floating island, when it rises above the watel•, is most elevated in the center, and on its being pierced with a fishing-rod, water has spouted up to the height of two feet, The marshy ground of the vale of Cashmere, and particularly around the city of Cashmere, containing many lakes, and liable to inundations, exhibits a peculiar form of human industry in its numerous FLOATING GARDENS, employed chiefly for the cultiva tion of cucumbers, melons, and water-melons. These floating gardens may be described as portions of the marshy ground artificially made to float, by matting through the roots of the reeds, sedges, and other plants about 2 ft. below the surface, upon which mud is then spread. The floating of the garden secures the soil and crop from destruction by inundations.
Floating gardens existed on the lake of Mexico before the conquest of Mexico by the Spaniards. The Mexicans had made great progress in the art of gardening, and particularly in the cultivation of flowers, which were much used both in their festivities and in their worship. How they were induced to attempt the formation of floating gardens, and at what period it was first done, are mere matters of conjecture. The shallowness of a great part of the lake was favorable to the success of the attempt, and perhaps the gradual receding of its waters may be reckoned among the reasons of the gradual diminution of the number of the floating gardens, which have almost ceased to be reckoned among the wonders of the world. The abbe Clavigero, in his History of Mexico, describes them as formed of wicker-work, water-plants, and mud; as sometimes more than 2-0 poles in extent; the largest ones commonly having a small tree in the con • ter, and sometimes a hut for the cultivator; and as employed for the cultivation both of flowers and culinary plants. Humboldt confirms this description, hut states that the real floating gardens, or chinampas, arc rapidly diminishing in number. The existing chinampas are in general not floating gardens, but plots of ground with very wide ditches between them, formed by heaping up earth from the ditches in the swamps or shallows at the side of the lake.
Great part of Bangkok, the capital of Siam, consists of floating houses. See BANG X0K.